1. Field of the Invention
The present invention relates generally to an improved slide switch apparatus having a movable contact held by a movable board arranged to be slidably contacted with a fixed contact so as to perform switch operation. More particularly, the present invention relates to an improved slide switch apparatus for accurately detecting a shift position of an automatic transmission of an automobile to prevent chatter from occurring between the movable contact and the movable board due to thermal expansion or change in tolerance, even when the switch is immersed in a high-temperature oil for use as an in-oil inhibitance switch installed in an automatic transmission, the switch being assembled onto a movable board in a one-touch manner.
2. Description of the Related Art
A conventional slide switch apparatus is shown, for example, in FIG. 7. This conventional slide switch comprises a movable board (a) having an engaging portion (d), and having in a movable contact attaching surface a support projection (c) for supporting a movable contact (b). An elastic rib (f) having an engaging projection (e) is provided for engaging the movable contact (b) opposite to the engaging portion (d).
Another conventional slide switch is shown, for example, in FIG. 8. This conventional slide switch comprises a movable board (g) having a projection (h) that is cold-crimped, and a movable contact (i) fixed to the movable board (g) through screw fastening or ultrasonic welding. The slide switch apparatuses shown in FIGS. 7 and 8 are disclosed in Japanese Unexamined Utility Model Publication No. S57-117523.
In the above-described conventional slide switch structure shown in FIG. 7, however, there has been a problem that chattering occurs due to occurrence of a gap (G) between the movable board (a) and the movable contact (b), as shown in FIG. 7. The gap (G) results from changes in tolerance introduced during forming the movable board (g) and the movable contact (b) or from thermal expansion caused when the apparatus is installed within an automatic transmission of an automobile to be used by immersion in a high-temperature oil.
Furthermore, it is impossible in the conventional slide switch structure shown in FIG. 8 to assemble the movable contact (i) onto the movable board (g) in a one-touch manner. Moreover, there has been a problem that chattering occurs in the movable contact (i) due to loosening of crimping in the projection (h) during service in an immersed state in a high-temperature oil over a long period of time.